Clashes broke out Sunday between Iranian border guards and Taliban forces, officials said, with the Afghan side confirming one of their border officers was killed and another wounded.
Both sides accused the other of opening fire first.
"There was a clash between the border guards of the Islamic Republic of Iran and the Taliban forces", Meysam Barazandeh, governor of Iran's Hirmand county, was quoted as saying by the Fars news agency.
He added that "the conflict was brief and has ended."
Fars reported that clashes took place on the Iranian side of the border, in the Shaghalak area of Hirmand country, in the southeastern province of Sistan-Baluchestan.
"A border violation by the Taliban took place today," Barazandeh said, adding that "our forces gave the necessary response", and that there "were no casualties" on the Iranian side.
Iran's Tasnim news agency said Taliban forces shot at some houses in the town of Dust Mohammad, which was followed by an exchange of fire "for several minutes."
A statement issued by Afghanistan's Nimroz provincial information centre blamed Iranian border guards for the incident.
"Iranian border forces fired at a patrol of our border forces in Kang district of Nimroz province," the statement said.
"After that they (Iranian forces) fired in the area with light and heavy weapons. In this shooting, one of our border force personnel was martyred and another injured," it added.
Last month, Iran's foreign ministry reported the death of an Iranian border guard in an "incident" at a border crossing with Afghanistan, also in Sistan-Baluchestan.
Iran, like many other nations, has so far not recognised the new government formed by the Taliban after it took power amid a hasty withdrawal by US-led foreign forces in August 2021.
While Iran insists that the Taliban form an inclusive administration, the Islamist movement has formed an all-male cabinet made up entirely of members of the group, and almost exclusively of ethnic Pashtuns.
Water rights issues have also increased tensions between the neighbours.
In January, demonstrators in Sistan-Baluchestan rallied at a border crossing for a protest over water from the Helmand River.
Tehran has hosted millions of Afghan refugees for decades, but fresh arrivals have entered the country since the Taliban's return to power.
Iran has long had testy relations with the Taliban, who raided Tehran's consulate in the northern Afghan city of Mazar-i-Sharif in 1998, killing 10 diplomats and a journalist.
The Taliban said the raid was carried out by a renegade force acting against orders.